1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of manufacturing a semiconductor device comprising surface processing of an aluminum film.
2. Description of the Related Art
When a semiconductor wafer having an aluminum film formed thereon is processed so as to expose the aluminum, processing reaction products, resist residues, re-deposited substances and the like remain on the aluminum film.
For example, when an aluminum film formed on a barrier metal film is patterned together with the barrier metal film, using a resist mask, by means of an etching gas comprising a fluorocarbon-based gas or the like, and then the resist mask is removed by dry etching, carbon-based residues derived from the resist remain on the upper surface of the resulting aluminum pattern. In addition, reaction by-products of the aluminum with the etching gas such as a fluorocarbon-based gas are deposited on the side wall surface of the aluminum pattern. Further, silicon-based substances derived from the underlying silicon oxide are also deposited on the side wall surface.
Further, when a contact hole is formed in a silicon oxide insulation film or a silicon nitride insulation film formed on an aluminum wiring layer to partially expose the aluminum wiring layer by etching with a gas comprising a fluorocarbon-based gas, reaction by-products of the aluminum with the fluorocarbon or the like are deposited on the surface of the exposed aluminum wiring layer. In addition, silicon-based reaction by-products derived from the silicon oxide insulation film are also deposited.
These residues (after-processing residues) that remain on the aluminum film after processing often lower the performance of the finally obtained semiconductor device if they are not removed.
Conventionally, organic amine-based chemicals have been used to remove the after-processing residues on the aluminum film, but their removing power is poor. Recently, acid-based or organic solvent/fluorine mixture-based chemicals have been used (see, for example, Jpn. Pat. Appln. KOKAI Publication Nos. 6-45296 and 10-303197).
However, anions (e.g., F−, Cl−, Br−, I−, Sox−, NOx−, and POx−) that are acidic components in these chemicals or organic acid anions (e.g., carboxyl group (—COO−), sulfone group (—SOx−), and nitro group (—NOx−)) remain on an aluminum surface after processing, causing aluminum corrosion after processing.